Astronomy Ch 6 The Earth
Terms in this set (28)
the light emitted by atoms and molecules in the upper atmosphere. This light is a result of magnetic disturbances caused by the solar wind. Often called the northern or southern lights.
the rising and sinking motions uin a liquid or gas that carry heat upward through the material. Convection is easily seen in a pan of heated soup on a stove.
a deflection of a moving object caused by its motion across the surface of a rotating body. The Coriolis effect makes storms on Earth spin, generates large-scale wind systems, and creates cloud belts on many of the planets.
the rigid surface of a planet, moon, or other solid body.
the atoms produced by the decay of a radioactive element. For example, uranium decays into lead. These lead atoms are daughter atoms.
the mass of a body or region divided by its volume.
the separation of previously mixed materials inside a planet or other object. This is the same separation that occurs when a dense material, such as iron, settles to the planets core while low density material floats to the surface.
a phenomenon in which the Earth's surface temperature has been observed to increase significantly over the last century. Most scientists attribute the change to increasing levels of gases that cause the greenhouse effect, released by human activities such as burning fossil fuels and deforestation.
the trapping of heat by a planet's atmosphere, making the planet warmer than would otherwise be expected. Generally the greenhouse effect operates if visible sunlight passes freely through a planet's atmosphere but the infrared radiation produced by the warm surface cannot escape readily into space, because of gases such as carbon dioxide or water vapor.
a narrow stream of high-speed wind that blows in the atmosphere of a planet. Such winds occur on Earth and many other planets.
liquid or outer core
the molten interior of a planet.
a representation of the means by which magnetic forces are transmitted from one body to another. A compass needle points along the direction of the Earth's magnetic field.
magnetic lines of force
fictitious lines used to visualize the orientation and strength of a magnetic field.
the solid, outer part of a planet. This part is immediately below the crust and may flow very slowly due to heat rising from the core.
a form of oxygen consisting of three oxygen atoms bonded together. Its chemical symbol is O3. the ozone in our atmosphre absorbs, and thus shields us from, the Sun's harmful ultraviolet radiation.
the idea that the crust of the Earth (or some other planet) is divided into large regions (plates) that move very slowly over the planet's surface. Interaction between plates at their boundaries creates mountains and activity such as earthquakes.
the property of a magnet that causes it to have a north and south pole.
the slow change in direction of the pole (rotation axis) of a spinning body or of the orientation of an orbit.
the breakdown of an atomic nucleus by the emission of subatomic particles.
an element that undergoes radioactive decay and breaks down into a lighter element.
the breaking apart of a continental plate.
waves generated in the Earth's interior by earthquakes. Similar waves occur in other bodies. Two of the more important varieties are S and P waves. The former can travel only through solid material; the latter can travel through either solid or liquid.
material composed of silicon and oxygen, and generally containing other substances as well. Most ordinary rocks are silicates. for example, quartz is silicon dioxide.
solid or inner core
The inner iron-nickel core of the Earth or another planet. Despite its high temperature, the core is solid because it is under great pressure.
a layer of Earth's atmosphere extending from about 12 to 50 km above the surface. A layer of ozone is found there.
the sinking of one crustal plate where it encounters another.
the lowest layer of the Earth's atmosphere extending up to about 12 km, where convection leads to clouds and precipitation.
Van Allen radiation belts
doughnut-shaped regions surrounding the Earth containing charged particles trapped by the Earths magnetic field.